Because the Queen is a player's most powerful Piece, it's tempting to thrust her straight into the game; to lead the attacks and capitalize upon her might, to bring about a swift and crushing victory.

The problem with this approach is that it doesn't factor in the Queen coming under attack from the opposing army.

No problem, you might think ... "I'll just move the Queen to safety, if she's attacked."

Yet, therein lies the very problem!

Having to move the Queen more than once, during the opening, violates one of the major principles of Development Strategy: "In the Opening, seek to move each Piece ONCE only, per turn."

By moving Pieces more than once, you risk your opponent gaining sufficient, positional advantage, which a lead in development can bring and which could severely restrict your own positional options ...

Falling behind in development can put you on the back foot for the remainder of the game; always playing second-fiddle to your opponent's superior move options, with your reactionary predicament pulling you towards your own demise.

Your objective, during the Opening - besides Castling the King to safer territory - is to develop your army as quickly as possible, to be ready for the forthcoming Middlegame battle.

If you're having to prat-about moving and re-moving your threatened Queen, it's obvious that those moves are being made at a detrimental cost to the overall Development of the remainder of your army.

One intriguing aspect of Chess is how each army starts a game with its Pieces in relatively Weak positions - they certainly aren't on squares that maximize their potential and respective powers of movement.

By leaving your Pieces on their starting squares and failing to develop them, you severely handicap your ability to thwart any attack, directed at your King.

A secondary consequence is you handicap your ability to defend your other Pieces.

It should be pointed out that there are tactical decisions made, whereby a player will deliberately allow a Piece to be captured, in order to gain advantage elsewhere ...

We're not talking about tactical sacrifices, here.

We're focussing on negligency - moving Pawns and Pieces without considering the consequences - no tactical reasoning; no strategic ploy ... Just pure, absentmindedness in your game play.

If you leave a Piece negligently undefended, it's likely it could be captured WITHOUT your ability to capture back.

... And, without playing for some sort of gain elsewhere; if you allow your opponent to capture a Piece, without reply, you will be reducing the effectiveness of your army.

Just take a look at the potential square coverage you'd be throwing away, if just ONE Piece were to be captured, without reply:

PieceLost

Maximum SquareCoverage Lost *

OptimalSquares **

Knight
Bishop
Rook
Queen

8
13
14
27

c3-c6, d3-d6, e3-e6, f3-f6
d4-d5, e4-e5
all over
d4-d5, e4-e5

* These numbers are based on each Piece having a clear, unobstructed view and getting each respective Piece onto a square - ** the Optimal Square - where it can cover the most number of squares, from its position.

Of all these Error Management examples, Weakening your King's position is probably the primary mistake to avoid.

While one objective is to build up an attack that will, hopefully, result in "Checkmating" your opponent's King; your other, primary objective is to make sure your own King's position is as safe as it can be.

All you're doing is making pointless work for yourself if, as you attempt to "Checkmate" your opponent's King, you allow your own King to become exposed and vulnerable to attack, itself.

The following are all situations whereby your King's position can become Weakened:

Leaving your King in its central, un-Castled starting position. As your Pawns begin to advance, they leave access points for your opponent's material ... This can't be helped and is a natural by-product of development ...

But, it's clearly not a wise idea to leave your King in sight of potential attack - if it gets "Checked", you will have to spend a turn or more getting it out of "Check" and this can allow your opponent to steal a lead in development. Not good.

The safest option, during the respective Opening & Middlegame phases, is to transport your King to the outer region of the Board, by Castling.

The closer a King sits to the central squares, the more troops it requires to protect it. It's far easier to defend the King when there's only a small window through which the enemy can attack, which is what Castling helps to achieve ...

With the King easier to protect, you'll tie-up fewer units of your army, therefore you'll have a greater proportion of your force to launch your assault on the enemy King's position.

Castling your King and then moving the defensive wall of Pawns, from in front. Those Pawns should remain in place, for as long as possible ...

By remaining 1 square in front of the King, direct or diagonally, then, should one of those Pawns get captured, the King will be close enough to capture the attacker.

Now, with all that said, two occaisions arise when one of the Pawns may be advanced one square:

To "Fianchetto" a Bishop - as this reinforces the Castled King's Stronghold.

To create "Luft" - you advance a Pawn to give the Castled King an escape route, in order to prevent a Back Rank Mate

So, the position of the Pawns, to the King, acts as a slight deterrant to your opponent's army.

Yes, with enough support, this Castled King's position can be breeched; but it can't be done in a single turn and will require more moves, by your opponent, to build up an attack which, should give you time to spot the trouble brewing and reinforce the threatened position.

Allowing your King to become trapped - or "Smothered" - by its surrounding Pawns & Pieces. This can result in losing the game by "Smothered Mate".